Driving and control gear for coal ploughs and other mining machines



1965 J. L. J. VAN VROONHOVEN 3,

DRIVING AND CONTROL GEAR FOR COAL PLOUGHS AND OTHER MINING MACHINES Filed Feb. 18, 1964 cl sd l i GlIOffl I g g I 81 53? fiw i/vra/e United States Patent 3,293,521 DRIVING AND CONTROL GEAR FGR COAL PLOUGHS AND OTHER MINING MACHINES Jan L. J. van Vmonhoven, Heerlen, Netherlands, assignor to Stamicarbon N.V., Heerlen, Netherlands Filed Feb. 18, 1964, Ser. No. 346,385 Claims priority, application Netherlands, Feb. 19, 1963, 289,204 5 Claims. (Cl. 318-281) The present invention relates to an operating and safety device for a reciprocating winning machine in a mine and, more particularly, to a machine of this type, e.g. a coal plough which is hauled to and fro along the coal face of a normally slightly inclined seam in a coal mine.

In know reciprocating winning machine arrangementsa switch is fitted at each end of the face worked by the machine, these switches being operated when the machine passes by. An operator starts the plough and then only has a checking function as the plough travels up and down automatically. A drawback of the known arrangements has been the risk of the plough being started in the wrong direction when it has reached the end of its travel and is stopped there. A11 object of the invention is to provide means to start the plough in the proper direction when a command is given after the plough has stopped at one of the ends of its travel due to power failure or at the command of the operator.

Ancillary to the preceding object it is a further object of the invention to prevent automatic re-start of the plough after is has been stopped due to a power failure.

An additional object is to provide means whereby the operator may choose the direction in which the plough starts.

Further objects of the invention will become more fully apparent when considered in light of the following detailed description of an illustrative embodiment of the invention and from the appended claims.

The illustrative embodiment may be best understood by reference to the accompanying drawings wherein:

FIGURE 1 is a block diagram illustrating the basic operation of a reciprocating winning machine as employed with the operating and safety device of the invention; and

FIGURE 2 is a schematic diagram of the control circuit of the invention.

Briefly, the invention is characterized by two switches that are fitted at each end of the face worked by the machine and which are operated successively when the machine passes by. Associated with these switches are two memories, operable between two states, that are brought to, or maintained, in one state by the switches which, as viewed from the middle of the travel, are first operated. The remaining switches each belong to separate memories to bring, or maintain them in the other state. Control means are connected with the memories, which means serve to reverse the direction of travel of the machine automatically at the ends of the face to be ploughed and which permit the machine to travel towards the other end only, when the machine has been stopped non-automatically at one of the extreme ends of the face.

The switches may be of various types and controlled in different ways. Use might for instance be made of photoelectric cells and a beam of light interrupted by the plough. A very suitable embodiment has been found by mounting switches within glass, protected against damage in a fixed position, and operating them by means of a magnet fitted on the plough. Various types of memories may also be employed.

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Preferably, the device is characterized by retardation means in the control means for starting. When the plough is automatically reversed it is then possible to stop it with certainty at the extreme end of the face to be ploughed. A retardation of l to 2 seconds suffices. It is furthermore contemplated to provide adjustable retardation means for automatically stopping the plough at the ends of the face. With these means the plough can be made to run to the end, independently of the positioning of the last switch. It will be sufficient if this time can be adjusted between 01 second.

Preferably, the memories are independent of the main supply voltage, that is to say that the information remains stored ifthe main supply voltage is interrupted. When the memories consist of polar relays with two stable positions, it is not difficult to make the circuit satisfy this condition.

The operation of the invention will now be set forth in detail with reference to the drawings. In FIGURE 1 of the drawings KS is a coal plough which moves up and down along sections X, Y, and Z of a coal face. At the transition areas between adjacent sections the plough meets and operates switches a, b, c, and d. The switches c and d are positioned near the upper end, the so-called supply end, of the face. The switches a and b are located near the lower end thereof, the so-called delivery end. For the sake of clarity, the reciprocating line along which the plough moves up and down has been drawn as separate lines. The switches are connected to two memories GI and GII. As the plough begins to move downwardly from section Z, memory G1 is initially off and memory GII on. The plough passing switch d produces no effect. When the plough passes switch c, memory G1 is switched on. As the plough passes switch a, there is no change produced. However, when the plough passes switch b, memory GII is switched off, after which the plough moves on to the end of its downward travel, stops, starts in the opposite direction. In its upward movement the plough passes switch b without any effect, cuts in memory GII by means of switch a, passes switch 0 without any effect, cuts out memory GI by means of switch d, moves on to the end of its upward travel, stops, starts in the opposite direction, etc. The distances between the switches a and b and between the switches c and d consequently cause, as it were, a hysteresis (h) pattern of operation.

FIGURE 2 illustrates the control means by which these and other operations are realized. In this diagram seven sections are set forth. These include: a main section 7, a control section 1, a memory section 2, a transmission section 3, two retardation sections 4 and 5, and a transmission section 6.

Parts indicated in the main section are fuses V, an earth-fault relay A, two electrohydraulic valves EH and EH for switching on the hydraulic motors of the plough, and two pilot lamps L. Throughout the diagram resistances are indicated by R, condensers by C, rectifiers by g, transistors by T, and potentiometers by Ri.

In the control section 1 there are two pressbuttons Op (for up) and Nr (for down) and a stopping switch Sp. Relays O, S, and N (indicated by squares) have been incorporated in the circuits of these buttons and switches. These relays, as well as others to be hereinafter described, are bridged by a capacitor and resistor in series to limit high currents when the relays are opened and closed. Hereinafter contacts of relays will be indicated by the sections in which they are incorporated. In the drawing these contacts are indicated by the letter of the relay. Thus the contacts of relay 0 in the sections 1, 2, 4 and 5 are indicated by O and in the following explanation of the operation by O1, O2, 0-4 and O5.

In the memory section 2 are shown the above mentioned switches a. l], c, and d (illustrated also in FIGURE 1) and two polar memory relays GI and GII, each with two windings. In the circuits of these relays, rectifiers g are employed to avoid induction currents, and the opening of the circuit of one relay coil will not close the circuit of the other coil of the same relay. In the transmission section 3 each memory has a contact in series with a transmission relay I or II (shown as squares). In the retardation sections 4 and 5 condenser connections provide for the retardation. If the changeover contacts I and II are in the position shown in the drawing, the retardation time is e.g. 2 seconds; after the circuit via contact I (II) is closed the tension of the condenser in the vertical line reaches in this time the value that is necessary to make the transistors conducting so that relay U (D) is excited. If the changeover contacts I and II are in the other position, the retardation time is fixed by the time in which the tension of the condenser in the vertical line has fallen so far that the transistors are not longer conducting; in the closed circuit comprising the condenser, the potentiometer Ri and a resistance R, that retardation time can be adjusted by means of the potentiometer Ri and is e.g. -1 second. The rectifiers above relays U and D protect the transistors. Relays U of section 4 and D of section have respective contacts in the transmission section 6, by means of which relays UO, or OD, may be selectively energized to excit the electrohydraulic relays EH or EH respectively. If the plough is stationary in section Y (FIG. 1) the two memories GI and GII (section 2) are switched on and the contacts GL3 and GII-3 are open, as indicated in FIGURE 2. Before starting, switch Sp must be closed. If button Op is now pressed, relay 0 is excited. As a result the contacts 0-1, 0-2 and 0-4 are closed and contact 0-5 is changed over. Relay S of section 1 is then excited causing contact S1 to be closed, S4 to be changed over and S5 to be changed over. This causes the relay U to be excited after 2 seconds, this delay being due to the operating characteristics of the condenser circuitry. As a result contact U-6 closes thereby exciting relay OU. As a result, contact OU-7 is closed, and valve EH is excited. Accordingly, the plough starts moving up, and a pilot lamp L lights up. Button Op can now be released, as contact S1, which is a holding contact, has taken over the function of this button.

At the end of section Y the plough operates switch 0. This switch closes and opens, but, as the memory relays GI and GII receive an impulse passing through the same winding as the impulse last received through switch a, this impulse produces no effect on the polar relays. Subsequently, switch d closes and opens. As a result, memory GI assumes the other position and contact GI-S closes. Relay I is thereby excited and its contacts asssume the following positions: Ilt open, I2 closed, I4 changed over, I5 closed. This causes relay U to drop out after a delay (adjustable from 01 second), as a result of which the relay OU and then the valve EH drops out, so that the plough stops. The change over of I5 permits relay D to be excited after a 2 second delay which causes the relay OD, and then the valve EH to be excited. The plough accordingly starts moving down.

If the plough is stopped when it is in section Z, there is no delay. When switch Sp is turned to the off position, relay S drops out so that it contacts 8-4 and 8-5 change over. The collector tension of the transistors becomes now almost zero via (see section 4-) a low resistance R (below Ri) contacts S, N, D, and U and a low resistance R above the transistors. Now relay U drops out immediately. The memories remain in the same position. To switch the device on again in the up direction is impossible, since contact Il is open.

The plough passing switch d in the down direction produces no effect. When it passes switch 0, memory G1 is again out in.

In all sections stopping is effected without delay. In section Y the plough can be started in both directions. Thus, if the plough hits on hard coal, it is possible to move the plough a few times up and down along any given length of face.

It is not necessary to stop the plough to change its direction when it is in section Y. When the plough is moving down it is enough to press button Op (section 1), relay 0 is now excited; contact O5 is changed over; relay D drops out without delay; relay OD drops out, as does relay EH The plough stops immediately. After two seconds relay U will be excited, as will relay 0U, and after that, relay EH The plough starts in the other direction.

In case of power failure relay 8 drops out and opens contact S-l. Consequentb the plough cannot start moving of its own accord after power has been restored, even if switch Sp is closed. It is necessary again to operate press-button Op or N)".

The device according to the invention is very reliable and economically attractive, raises safety considerably, and is very simple to operate.

The above-described embodiment is illustrative of a preferred embodiment of the invention but is not intended to limit the possibilities of insuring the features of controlled, safe operation of the reciprocating machine. The apparatus disclosed herein is an example of an arrangement in which the inventive features of this disclosure may be utilized, and it will become apparent to one skilled in the art that certain modifications may be made within the spirit of the invention as defined by the appended claims.

What is claimed is:

1. A device for driving and controlling coal ploughs and other mining machines reciprocally movable between the ends of a coal face of a mine comprising:

(a) a pair of switches at each end of the face worked by the machine and positioned in operative relationship with respect to the machine to be successively actuated by the passage of the machine thereby;

(b) a pair of memories connected to said switches and operable between two states in accordance with the actuation of said switches by the machine;

(c) the first switch of each pair of switches being connected to the memories so as to maintain said memories in a first state when said first switch is actuated by the machine as it passes thereby from a position intermediate the first switches of each switch pair;

(d) the second switch of each pair of switches being connected to said memories such that as the machine moves from a position intermediate the first one of a pair of switches past the second switch of the pair, a memory is changed to its second state; and such that as the machine moves past the second switch from a position at one end of the face toward a position intermediate the first and second switches of the pair, the memory is maintained in its second state;

(e) said first switch of each pair of switches also being connected to the memories such that as the machine moves past the first switch from a position intermediate the first and second ones of a switch pair toward a position intermediate the first switches of each pair, the said memory is returned to its first state; and

(f) control means connected to said memories, said control means including means for directing the movement of said machine, the directing means being responsive to the states of said memories for automatically reversing the movement of the machine at the ends of the face, said control means further including means for partially interrupting the operation of said directing means when the machine is nonautomatically stopped at an end of the face whereby said machine is permitted to travel only toward the opposite end of the face.

5 6 2. A device according to claim 1, further comprising References Cited by the Examiner retardation means for delaying the starting of said ma- UNITED STATES PATENTS chine, said means being connected in the circuit between the memories and the control means. g g 3. A device according to claim 1, further comprising 5 I 11/1959 g 1 318 282 retardation means for automatically stopping said ma- 2922O53 1/1960 Ste 61 318:282 Chme at i face" 3,129,369 4/1964 Littwin 318-282 4. A device accordmg to claim 1, wherein the memones 3 213 342 10/1965 Littwin are independent of the main supply voltage.

5. A device according to claim 1, Wherein the memories 10 ORIS RADER, Examine"- comprise polar relays with tWo stable states. 3 DOBECK Assistant Examiner 

1. A DEVICE FOR DRIVING AND CONTROLLING COAL PLOUGHS AND OTHER MINING MACHINES RECIPROCALLY MOVABLE BETWEEN THE ENDS OF A COAL FACE OF A MINE COMPRISING: (A) A PAIR OF SWITCHES AT EACH END OF A FACE WORKED BY THE MACHINE AND POSITIONED IN OPERATIVE RELATIONSHIP WITH RESPECT TO THE MACHINE TO BE SUCCESSIVELY ACTUATED BY THE PASSAGE OF THE MACHINE THEREGY; (D) A PAIR OF MEMORIES CONNECTD TO SAID SWITCHES AND OPERABLE BETWEEN TWO STATES IN ACCORDANCE WITH THE ACTUATION OF SAID SWITCHES BY THE MACHINE; (C) THE FIRST SWITCH OF EACH PAIR OF SWITCHES BEING CONNECTED TO THE MEMORIES SO AS TO MAINTAIN SAID MEMORIES IN A FIRST STATE WHEN SAID FIRST SWITCH IS ACTUATED BY THE MACHINE AS IT PASSES THEREGBY FROM A POSITION INTERMEDIATE THE FIRST SWITCHES OF EACH SWITCH PAIR; (D) THE SECOND SWITCH OF EACH PAIR OF SWITCHES BEING CONNECTED TO SAID MEMORIES SUCH THAT AS THE MACHINE MOVES FROM A POSITION INTERMEDIATE THE FIRST ONE OF A PAIR OF SWITCHES PAST THE SECOND SWITCH OF THE PAIR, A MEMORY IS CHANGED TO ITS SECOND STATE AND SUCH THAT AS THE MACHINE MOVES PAST THE SECOND SWITCH FROM A POSITION AT ONE END OF THE FACE TOWARD A POSITION INTERMEDIATE THE FIRST AND SECOND SWITCHES OF THE PAIR, THE MEMORY IS MAINTAINED IN ITS SECOND STATE; 